Nobody can veto a release, period. It is therefore impossible for anything to be a showstopper unless it is a pending veto of a commit or the group makes a decision by majority of -1 on any release until the problem is fixed. If the RM doesn't think that is the case, then they should move the issue out of that category. If anyone else has a problem with that, they are perfectly capable of calling for a vote on not releasing the code until the issue is fixed.
The only reason the showstopper category exists is because I needed a place to keep track of problems that we all agreed to fixing before I could cut a release. That is all. Now it is just being abused. ....Roy
